Upload
others
View
2
Download
0
Embed Size (px)
Citation preview
The present document has been developed within the NMSC and may be further elaborated for the purposes of
NMSC. This specification is provided for development work of GK2A UHRIT receiving station.
Issue 1.0 MAY 31, 2019
GK2A UHRIT Mission Specification Document
NMSC
GK2A UHRIT Mission Specification Document Issue 1.0 MAY 31, 2019
2
Keywords
< GK2A, UHRIT, LDUS >
KMA
Postal address
45 Gisangcheong-gil, Dongjak-gu
Seoul 156-720, Republic of KOREA
Tel.: +82-2-2181-0900
NMSC
636-10 Gwangheywon-myeon, Jincheon-gun,
Chungbuk, 365-831, Republic of KOREA
Tel.: +82-70-7850-5709
Internet
http://www.kma.go.kr(KMA)
http://nmsc.kma.go.kr(NMSC)
NMSC
GK2A UHRIT Mission Specification Document Issue 1.0 MAY 31, 2019
3
Table of Contents
Table of Contents ..................................................................................................................................................... 3
Figures ..................................................................................................................................................................... 5
Tables ...................................................................................................................................................................... 6
Foreword .................................................................................................................................................................. 8
1 INTRODUCTION ........................................................................................................................................ 9 1.1 Purpose .................................................................................................................................................... 9 1.2 References ............................................................................................................................................... 9 Abbreviations ......................................................................................................................................................... 10
2 OSI REFERENCE MODEL ....................................................................................................................... 11 2.1 Communication Concept of UHRIT ..................................................................................................... 11
3 APPLICATION LAYER ............................................................................................................................ 13 3.1 Data Type .............................................................................................................................................. 13 3.1.1 Image Data....................................................................................................................................... 13 3.1.2 Additional Data ............................................................................................................................... 14
4 PRESENTATION LAYER ........................................................................................................................ 15 4.1 Segmentation of GK2A UHRIT ............................................................................................................ 15 4.2 UHRIT File Structure ............................................................................................................................ 15 4.3 File Type of UHRIT .............................................................................................................................. 16 4.4 Header Records of GK2A UHRIT File ................................................................................................. 16 4.4.1 Header Type #0 – Primary Header .................................................................................................. 17 4.4.2 Header Type #1 – Image Structure .................................................................................................. 18 4.4.3 Header Type #2 – Image Navigation ............................................................................................... 18 4.4.4 Header Type #3 – Image Data Function .......................................................................................... 19 4.4.5 Header Type #4 – Annotation Text ................................................................................................. 19 4.4.6 Header Type #5 – Time Stamp ........................................................................................................ 20 4.4.7 Header Type #6 – Ancillary Text (Not used) .................................................................................. 20 4.4.8 Header Type #7 – Key Header ........................................................................................................ 20 4.4.9 Header Type #128 – Image Segmentation Identification ................................................................ 21 4.4.10 Header Type #129 – Encryption Key Massage(Not used) .............................................................. 21 4.4.11 Header Type #130 – Image Compensation Information .................................................................. 21 4.4.12 Header Type #131 – Image Observation Time ................................................................................ 22 4.4.13 Header Type #132 – Image Quality Information ............................................................................. 22 4.5 UHRIT File Name ................................................................................................................................. 22 4.5.1 Image Data File Name ..................................................................................................................... 23 4.6 File Type vs. Header Implementation.............................................................................................. 24
5 SESSION LAYER ...................................................................................................................................... 25 5.1 Compression .................................................................................................................................... 25 5.2 Encryption ....................................................................................................................................... 25
6 TRANSPORT LAYER ............................................................................................................................... 26 6.1 Transport File(TP_File) ................................................................................................................... 26 6.2 Space Packet (CP_PDU) ................................................................................................................. 27
NMSC
GK2A UHRIT Mission Specification Document Issue 1.0 MAY 31, 2019
4
7 NETWORK LAYER .................................................................................................................................. 29
8 DATA LINK LAYER ................................................................................................................................ 30 8.1 M_PDU ........................................................................................................................................... 30 8.2 AOS Transfer Frame ....................................................................................................................... 31 8.3 CADU .............................................................................................................................................. 32
9 PHYSICAL LAYER................................................................................................................................... 33 9.1 Baseband Layer Frame (BBFRAME) ............................................................................................. 33 9.2 XFEC Frame (XFECFRAME) ........................................................................................................ 34 9.3 Physical Layer Frame (PLFRAME) ................................................................................................ 34
APPENDIX ............................................................................................................................................................ 36 Appendix A: GK2A UHRIT Data Format and Procedures .................................................................................... 36 Appendix B: GK2A LRIT/HRIT/UHRIT APID and VCID .................................................................................. 36
NMSC
GK2A UHRIT Mission Specification Document Issue 1.0 MAY 31, 2019
5
Figures
Figure 2.1 Definition of GK2A UHRIT Data Type
Figure 3.1 GK2A FD Image
Figure 4.1 UHRIT File Structure
Figure 5.1 Session Layer Processing
Figure 5.2 Principle of Encryption and Decryption for UHRIT
NMSC
GK2A UHRIT Mission Specification Document Issue 1.0 MAY 31, 2019
6
Tables
Tabel 2.1 OSI Layer Functionalities for GK2A UHRIT Service
Tabel 3.1.1 Channel and Resolution of GK2A Image Data
Tabel 4.1 UHRIT Image Data Segment File Structure
Tabel 4.2 UHRIT File Type
Tabel 4.3 UHRIT Header Type
Tabel 4.4 Header Type #0 – Primary Header
Tabel 4.5 Header Type #1 – Image Structure
Tabel 4.6 Header Type #2 – Image Navigation
Tabel 4.7 Header Type #3 – Image Data Function
Tabel 4.8 Header Type #4 – Annotation
Tabel 4.9 Header Type #5 – Time Stamp
Tabel 4.10 Header Type #7 – Key Header
Tabel 4.11 Header Type #128 – Image Segmentation Identification
Tabel 4.12 Header Type #130 – Image Compensation Information
Tabel 4.13 Header Type #131 – Image Observation Time
Tabel 4.14 Header Type #132 – Image Quality Information
Tabel 4.15 File Name of Image Data
Tabel 4.16 Additional Data File Name
Tabel 4.17 File Type vs. Header Implementation
Tabel 4.17 File Type vs. Header Implementation
Tabel 6.1 Transport File Structure
Tabel 6.2 UHRIT TP_Header
Tabel 6.3 Space Packet Structure
Tabel 6.4 Space Packet Primary Header
Tabel 6.5 Space Packet Secondary Header
Tabel 8.1 M_PDU Structure
Tabel 8.2 M_PDU Header
Tabel 8.3 AOS Transfer Frame Structure
Tabel 8.4 Transfer Frame Primary Header
Tabel 8.5 CADU Structure
Tabel 9.1 BBFRAME
Tabel 9.2 MATYPE-1 Field Mapping
Tabel 9.3 DVB-S2 FECFRAME for 8PSK 2/3
Tabel 9.4 DVB-S2 Physical Layer Framing
Tabel 9.5 DVB-S2 PLHEADER
Tabel 9.6 Parameters of UHRIT Communication Link
NMSC
GK2A UHRIT Mission Specification Document Issue 1.0 MAY 31, 2019
7
NMSC
GK2A UHRIT Mission Specification Document Issue 1.0 MAY 31, 2019
8
Foreword
This specification document has been produced by the National Meteorological Satellite Center (NMSC).
Should NMSC modify the contents of the present document, it will be re-released by NMSC with an identifying
change of release date and an increase in version number as follows:
Issue x.y
where:
x the first digit is incremented for all changes of substance, i.e. technical enhancements, corrections,
updates, etc.
y the second digit is incremented when editorial only changes have been incorporated in the
document.
NMSC
GK2A UHRIT Mission Specification Document Issue 1.0 MAY 31, 2019
9
1 INTRODUCTION
1.1 Purpose
The Ultra High Rate Information Transmission (UHRIT) specification of the GK2A was written in accordance
with ISO 7498 and the CCSDS Recommendation standard. This UHRIT Mission Specification defines the
structure and format of the UHRIT file and will provide a way to process and transmit GK2A satellite broadcast
data based on the OSI hierarchy.
This document is intended to distribute detailed specifications for providing meteorological data observed
through GK2A using UHRIT services.
1.2 References
Applicable documents:
[AD 1] KARI: ‘GK2A LRIT/HRIT/UHRIT Mission Specification for GK2A PDS Development’,
GK2-D0-600-012 F.03, Nov. 07 2018
[AD 2] CGMS: ‘Coordination Group for Meteorological Satellites LRIT/HRIT Global
Specification’, CGMS03 Issue 2.6
Reference documents:
[RD 1] CGMS: ‘LRIT/HRIT Global Specification’, Rev 2.6.August 1999
[RD 2] ISO: ‘Information Processing System - Open System Interconnection - Basic Reference
Model’, ISO standard 7498, Feb. 1982
[RD 3] CCSDS: ‘Networks and Data Links: Architectural Specification’, CCSDS
Recommendation 701.0-B-3-S, June 2001
[RD 4] KMA: ‘COMS LRIT Mission Specification’, Issue 1.2, November 30, 2010
[RD 5] KMA: ‘COMS HRIT Mission Specification’, Issue 1.2, November 30, 2010
[RD 6] ISO: ‘Information technology -- JPEG 2000 image coding system: Core coding system’,
ISO/IEC 15444-1:2004
[RD 7] CGMS: ‘LRIT/HRIT Global Specification’, Issue 2.8, 30 October 2013
[RD 8] CCSDS: ‘Time code formats’, CCSDS recommendation 301.0-B-3 January 2002
[RD 9] CCSDS: ‘AOS Space Data Link Protocol’, CCSDS 732.0-B-2, July 2006
[RD 10] ETSI: ‘Digital Video Broadcasting (DVB) Second generation framing structure, channel
coding and modulation systems for Broadcasting, Interactive Services, News Gathering and
other broadband satellite applications’, Part 1: DVB-S2, EN 302 307-1, V1.4.1
[RD 11] ISO: ‘Information Processing System - Open System Interconnection Basic Reference
Model’, ISO standard 7498, Feb. 1982
[RD 12] CCSDS: ‘TM Synchronization and Channel Coding’, CCSDS Recommendation 131.0-B-3-
September 2003
[RD 13] Data Encryption Standard (DES) Federal Information Processing Standard (FIPS) PUB 46-
2, U.S. Dept. of Commerce, National Institute of Standards and Technology, 30/12/93
[RD 14] CCSDS: ‘Space Packet Protocol’, CCSDS 133.0-B-1, September 2003
NMSC
GK2A UHRIT Mission Specification Document Issue 1.0 MAY 31, 2019
10
Abbreviations
AMI Advanced Meteorological Imager
APID Application Process Identifier
APNH Asia and Pacific in Northern Hemisphere
CADU Channel Access Data Unit
CVCDU Coded Virtual Channel Data Unit
CCSDS Consultative Committee for Space Data Systems
CGMS Co-ordination Group for Meteorological Satellite
COMS Communication, Ocean and Meteorological Satellite
CP_PDU CCSDS Path Protocol Data Unit
DES Data Encryption Standard
ECB Electronic Code Book (DES mode)
ENC Encryption Process
ELM Extended Local Model
ENH Extended Northern Hemisphere
FD Full Disk
GK2A Geo-KOMPSAT-2A
GRIB Gridded Binary
GTS Global Telecommunication System
HRIT High Rate Information Transmission
ISO International Organization for Standardization
JPEG Joint Photographic Expert Group
KMA Korea Meteorological Administration
LRIT Low Rate Information Transmission
LSB Least Significant Bit
LSH Limited Southern Hemisphere
MAC Media Access Control
MSB Most Significant Bit
NWP Numerical Weather Prediction
M_PDU Multiplexing Protocol Data Unit
OSI Open Systems Interconnection
RF Radio Frequency
S/C Spacecraft
SDUS Small-scale Data Utilization Station
TBC To Be Confirmed
TBD To Be Defined
TP_PDU Transport Protocol Data Unit
UHRIT Ultra High Rate Information Transmission
VCDU Virtual Channel Data Unit
WMO World Meteorological Organization
NMSC
GK2A UHRIT Mission Specification Document Issue 1.0 MAY 31, 2019
11
2 OSI REFERENCE MODEL
2.1 Communication Concept of UHRIT
The GK2A UHRIT dissemination service is based on the Open Systems Interconnection (OSI) Reference Model
in [RD2] and the CCSDS AOS in [RD3].
Table 2.1 presents the functionalities of the each OSI layer from the view of dissemination system.
Table 2.1 OSI Layer Functionalities for GK2A UHRIT Service
OSI 7 layers Layer functionalities
Application layer Acquisition of application data
Presentation layer Image segmentation,
UHRIT file structuring
Session layer Compression (if required)
Encryption (if required)
Transport layer Determination of APID
Split of files into source packet
Network layer Determination of VCID
Data link layer
Multiplexing,
Error of block unit detection,
Reed-Solomon encoding
Randomization
Attachment of sync marker
Physical layer
Serialization,
Viterbi encoding,
Modulation
This documentation defines data type of each layer as Figure S_PDU is file data of xRIT_Data compressed and
encrypted, each data format including S_PDU will described corresponding chapter.
NMSC
GK2A UHRIT Mission Specification Document Issue 1.0 MAY 31, 2019
12
Bit Stream
Application
Presentation
Session
Transport
Network
Data Link
Physical
Application
Presentation
Session
Transport
Network
Data Link
Physical
CADU CADU CADU
CA_PDU
S_PDU
CA_PDU CA_PDU
TP_PDU TP_PDU TP_PDU
xRIT_Data
Communication Media Space Path
Figure 2.1 Definition of GK2A UHRIT Data Type
NMSC
GK2A UHRIT Mission Specification Document Issue 1.0 MAY 31, 2019
13
3 APPLICATION LAYER
3.1 Data Type
The GK2A UHRIT service will provide specific application data from external systemin the Application Layer
as follows,
- Image Data: Full Disk(FD)
- Additional Data:
Alphanumeric text file
Level 2 Data(TBD)
3.1.1 Image Data
The type of image data consists of visible channel image and infrared channel image. The projection type of
GK2A UHRIT is GEOS. The images defining latitude, longitude, and size are distributed.
- Dissemination mode and image size:
FD 22,000 x 22,000 (VIS06)
FD 11,000 x 11,000 (VIS04, VIS05, VIS08)
FD 5,500 x 5,500 (IR)
- Dissermination time:
Within 3 minutes afer completion of observation(Observatio period: 10 minute)
Table 3.1.1 Channel and Resolution of GK2A Image Data
No. Name Wavelength Resolution bit
1 VI004 0.47 1 km 11
2 VI005 0.51 1 km 11
3 VI006 0.64 0.5 km 12
4 VI008 0.86 1 km 13
5 NR013 1.38 2 km 12
6 NR016 1.61 2 km 11
7 SW038 3.90 2 km 14
8 WV063 6.18 2 km 12
9 WV069 6.95 2 km 13
10 WV073 7.34 2 km 13
NMSC
GK2A UHRIT Mission Specification Document Issue 1.0 MAY 31, 2019
14
11 IR087 8.50 2 km 13
12 IR096 9.61 2 km 13
13 IR105 10.3 2 km 13
14 IR112 11.2 2 km 13
15 IR123 12.3 2 km 13
16 IR133 13.3 2km 13
Figure 3.1 GK2A FD Image
3.1.2 Additional Data
Additional data distributed through GK2A satellite broadcasting service are Alphanumeric Text and Level-2 data.
- Alphanumeric Text provides GK2A operation information, observation schedule, satellite
broadcast distribution schedule, algorithm update information, data processing parameters, and data
conversion factor.
- Level-2 data is provided with meteorological data and utilization data based on GK2A observation
data.
NMSC
GK2A UHRIT Mission Specification Document Issue 1.0 MAY 31, 2019
15
4 PRESENTATION LAYER
4.1 Segmentation of GK2A UHRIT
Image segmentation is performed for GK2A UHRIT dissemination services in real-time and for high flexibility
with the UHRIT compression/encryption schemes. Compression and encryption is processed with the unit of
segment. The whole UHRIT images are composed of a number of UHRIT files.
- UHRIT segment file size: Column x Line
Table 4.1 UHRIT Image Data Segment File Structure
GK2A UHRIT Image Data
Observation
Mode Segment Files
1 Segment Size
2 km 1 km 0.5 km
FD
Segment File #1 125 x 2,500 250 x 11,000 500 x 22,000
Segment File #2~#22 250 x 2,500 500 x 11,000 1,000 x 22,000
Segment File #23 125 x 2,500 250 x 11,000 500 x 22,000
4.2 UHRIT File Structure
GK2A UHRIT files are formatted data as shown in figure 4.1. An UHRIT files consists of one or more header
records and one data field. The primary header record defines the file type and the size of the complete UHRIT
file. The secondary header records include various information relating with the data field.
Header
Data Field Primary Header
(0#, Mandatory)
Secondary Header
( #1~#255, Optional)
Figure 4.1 UHRIT File Structure
NMSC
GK2A UHRIT Mission Specification Document Issue 1.0 MAY 31, 2019
16
4.3 File Type of UHRIT
GK2A UHRIT file types are described in Table 4.2. The file types (0… 127) have already been defined in [RD
1]. In addition, the mission specific file types (128… 255 have been reserved for the future GK2A UHRIT
service expansion.
Table 4.2 UHRIT File Type
Classification File Type
Code File Type Application data type contained in the data field
UHRIT basic
data
0 Image data FD observation data
(Normalized Geostationary Projection)
1 GTS
message Not used
2 Alphanume
ric text
Administrative messages including observation/
dissemination schedule
3 Encryption
key Message Not used
4~127 Reserved For further global use
Add data space 128~255 Reserved For further mission specific use
4.4 Header Records of GK2A UHRIT File
Table 4.3 UHRIT Header Type
Classificatio
n Code Header Record Type Remark
Global Header
Types
0 Primary header
1 Image structure
2 Image navigation
3 Image data function
4 Annotation
5 Time stamp
NMSC
GK2A UHRIT Mission Specification Document Issue 1.0 MAY 31, 2019
17
6 Ancillary text Not used
7 Key header
8 ~ 127 Reserved
Mission
Specific Header
Type
128 Image segment definition Image segment file information
129 Encryption key message header Not used
130 Image compensation info. header
131 Image observation time header
132 Image quality info. header
133 ~ 255 Reserved
4.4.1 Header Type #0 – Primary Header
This header provides the size of total UHRIT file(header records + data field). The padding data with the value
of “0x00” will be filled at the end of data field to be line with 64 bits alignment of DES encryption when the
encryption is applied.
Table 4.4 Header Type #0 – Primary Header
Classification Data Type Data Size
(Bytes) Value Remark
Header Type unsigned integer 1 0 Fixed value
Header Record
Length unsigned integer 2 16 Fixed value
File Type Code unsigned integer 1 Variable
0: Image data file
1: GTS message(Not used)
2: Alphanumeric text file
3: Encryption key message(Not used)
Total Header
Length unsigned integer 4 Variable Total Header Record size(Bytes)
Data Field Length unsigned integer 8 Variable Data Field size(bits)
NMSC
GK2A UHRIT Mission Specification Document Issue 1.0 MAY 31, 2019
18
4.4.2 Header Type #1 – Image Structure
This header provides number of bits per pixel, number of columns, number of lines of image structure, and
compression flag.
Table 4.5 Header Type #1 – Image Structure
Classification Data Type Data size
(Bytes) Value Remark
Header Type unsigned
integer 1 1 Fixed value
Header Record
Length
unsigned
integer 2 9 Fixed value
Number of bit per
pixel
unsigned
integer 1 Variable Input valid bit according to channel
Number of
columns
unsigned
integer 2 Variable
Variable size according to observation area
and channel
Number of lines unsigned
integer 2 Variable
Variable size according to observation area
and channel
Compression Flag unsigned
integer 1 Variable
Compression method
0: No compression
1: Lossless compression
2: Lossy compression
4.4.3 Header Type #2 – Image Navigation
This header provides the information of image projection on the earth .
Table 4.6 Header Type #2 – Image Navigation
Classification Data Type Data size
(Bytes) Value Remark
Header Type unsigned
integer 1 2 Fixed value
Header Record
Length
unsigned
integer 2 51 Fixed value
Projection Name Character 32 Variable Projection names as defined in [RD7]
GEOS(<sub_lon>)
CFAC integer 4 Variable Column scaling factor as defined in [RD7]
LFAC integer 4 Variable Line scaling factor as defined in [RD7]
NMSC
GK2A UHRIT Mission Specification Document Issue 1.0 MAY 31, 2019
19
COFF integer 4 Variable Column offset as defined in [RD7]
LOFF integer 4 Variable Line offset factor as defined in [RD7]
4.4.4 Header Type #3 – Image Data Function
This header provides the physical meaning of the image data. It is used to define images which require
establishing a relationship between their pixel count and physical units such as radiance/temperature or albedo.
Table 4.7 Header Type #3 – Image Data Function
Classification Data Type Data size
(Bytes) Value Remark
Header Type unsigned
integer 1 3 Fixed value
Header Record
Length
unsigned
integer 2 Variable Max. 65535
Data Definition
Block Character variable Variable Max. 65532 (TBD)
4.4.5 Header Type #4 – Annotation Text
This header provides the annotation record to allow quicker and easier detection of file contents.
Table 4.8 Header Type #4 - Annotation
Classification Data
Type
Data size
(Bytes) Value Remark
Header Type Unsigned
integer 1 4 Fixed value
Header Record
Length
Unsigned
integer 2 Variable Max. 67
Annotation Text Characte
r Variable Variable
Max. 64
File Name
IMG_FD_143_VI006_20180627_030000_01.uhrit
ADD_ANT_143_20180627_030000__01.uhrit
NMSC
GK2A UHRIT Mission Specification Document Issue 1.0 MAY 31, 2019
20
4.4.6 Header Type #5 – Time Stamp
This header provides processing time in session layer.
Table 4.9 Header Type #5 – Time Stamp
Classification Data Type Data size
(Bytes) Value Remark
Header Type Unsigned
integer 1 5 Fixed value
Header Record
Length
Unsigned
integer 2 10 Fixed value
Time Stamp
(CDS P Field)
Unsigned
integer 1 Variable P-Field fixed value according to [RD8]
Time Stamp
(CDS T Field)
Unsigned
integer 6 Variable T-Field fixed value according to [RD8]
4.4.7 Header Type #6 – Ancillary Text (Not used)
The header type #6 will be used for the GK2A UHRIT service expansion.
4.4.8 Header Type #7 – Key Header
This header provides the number of used encryption key.
Table 4.10 Header Type #7 – Key Header
Classificatio
n Data Type
Data size
(Bytes) Value Remark
Header Type Unsigned
integer 1 7 Fixed value
Header Record
Length
Unsigned
integer 2 7 Fixed value
Key Number Unsigned
integer 4 Variable
Index of the used encryption key
0: Encryption is not applied
NMSC
GK2A UHRIT Mission Specification Document Issue 1.0 MAY 31, 2019
21
4.4.9 Header Type #128 – Image Segmentation Identification
Table 4.11 Header Type #128 – Image Segmentation Identification
Classification Data Type Data size
(Bytes) Value Remark
Header Type Unsigned integer 1 128 Fixed value
Header Record Length Unsigned integer 2 7 Fixed value
Image Segment Seq.
No. Unsigned integer 1
Variabl
e Image segment sequence number
Total No. Image.
Segment Unsigned integer 1
Variabl
e Total number of Image segments
Line No. Image.
Segment Unsigned integer 2
Variabl
e Line number of Image segment
4.4.10 Header Type #129 – Encryption Key Massage(Not used)
4.4.11 Header Type #130 – Image Compensation Information
This header includes the image navigation parameters, such as COFF, LOFF, CFAC, LFAC for the entire image
data.
Table 4.12 Header Type #130 – Image Compensation Information
Classification Data Type Data size
(Bytes) Value Remark
Header Type Unsigned
integer 1 130 Fixed value
Header Record Length Unsigned
integer 2 Variable Max. 65535
Image Compensation
Information Character Variabel Variable Max. 65532
NMSC
GK2A UHRIT Mission Specification Document Issue 1.0 MAY 31, 2019
22
4.4.12 Header Type #131 – Image Observation Time
This header includes the observation time of image data as MJD (Modified Julian Day) format.
Table 4.13 Header Type #131 – Image Observation Time
Classification Data Type Data size (Bytes) Value Remark
Header Type Unsigned integer 1 131 Fixed value
Header Record Length Unsigned integer 2 Variable Max. 65535
Image Observation Time Character Variable Variable Max. 65532
4.4.13 Header Type #132 – Image Quality Information
This header represents Error pixel number of the whole image.
Table 4.14 Header Type #132 – Image Quality Information
Classification Data Type Data size (Bytes) Value Remark
Header Type Unsigned integer 1 132 Fixed value
Header Record Length Unsigned integer 2 Variable Max. 65535
Image Observation Time Character Variable Variable Max. 65532
4.5 UHRIT File Name
The file name of character strings is stored in the Annotation Header (Header Type # 4). The name of image data
files disseminated via UHRIT is defined as follows.
NMSC
GK2A UHRIT Mission Specification Document Issue 1.0 MAY 31, 2019
23
4.5.1 Image Data File Name
The example of UHRIT image data file name:
- IMG_AA_NNN_CHHnn_YYYYMMDD_hhmmss_NN.uhrit
The UHRIT file name of image data is used as follows,
Table 4.15 File Name of Image Data
File
Type
Observatio
n Mode
Sequence
No.
Spectra
l
Channel
Dissemination Time
Segmen
t File
No.
Ext.
Form IMG_ AAAAAAA_ NNN_ CHnnn_ YYYYMMDD_hhmmss_ NN .uhrit
Size 4 Bytes Maximum
8 Bytes 4 Bytes 6 Bytes 16 Bytes 2 Bytes 6 Bytes
Ex) IMG_ FD_ 143_ VI006_ 20180627_030000_ 01 .uhrit
- UHRIT Image Data File Type is indicated as IMG_
- Observation mode marked as AAAAAAA_
- Video sequence number starts from 00UTC in order of observation mode, and is indicated as NNN_
- The channel is divided into 16 channels and the central wavelength is marked as CHnnn_
- The sequence number of the split file starts from 01 for each observation image and is displayed as NN
The example of UHRIT additional data file name:
- ADD_AAAAAAA_NNN_ YYYYMMDD_hhmmss_NN.uhrit
The UHRIT file name of additional data is used as follows,
Table 4.16 Additional Data File Name
File
Type
Additional
Data Type Sequence No. Dissemination Time
Segment
File No. Ext.
Form ADD_ AAAAAAA_ NNN_ YYYYMMDD_hhmmss_ NN .uhrit
Size 4 Bytes Max
8 Bytes 4 Bytes 16 Bytes 2 Bytes 6 Bytes
Ex) ADD_ ANT_ 143_ 20180627_030000_ 01 .uhrit
- UHRIT Additional Data File Type is indicated as ADD_
- Additional Data Type is marked as AAAAAAA_
- The video sequence number is NNN_ in the order of the additional data type.
- The sequence number of the split files is 01 for each additional data type.
NMSC
GK2A UHRIT Mission Specification Document Issue 1.0 MAY 31, 2019
24
4.6 File Type vs. Header Implementation
Table defines the GK2A UHRIT mission specific use of header record types within certain UHRIT file types.
Table 4.17 File Type vs. Header Implementation
File types Header record types
0 1 2 3 4 5 6 7 128 129 130 131 132
0 Image data file ● ● ◎ ◎ ◎ ◎ ◎ ◎ ○ ◎ ○
1 GTS Message
2 Alphanumeric text file ● ◎ ◎ ◎
● As requested by [RD7] ◎ KMA mandatory use ○ KMA optional use
0 Primary header 128 Image segment identification
1 Image structure 129 Encryption Key message header
2 Image navigation 130 Image compensation info. header
3 Image data function 131 Image observation time header
4 Annotation 132 Image quality information header
5 Time stamp
6 Ancillary text
7 Key header
NMSC
GK2A UHRIT Mission Specification Document Issue 1.0 MAY 31, 2019
25
5 SESSION LAYER
The session layer includes the definition of data compression and encryption for each xRIT_Data transmitted as
file type from application layer. The output of the session layer to the transport layer is S_PDU containing the
compressed and encrypted data field.
The Session Layer generates S_PDU by applying to each UHRIT file from the Presentation Layer in the order of
compression and encryption.
Figure 5.1 Session Layer Processing
5.1 Compression
According to [RD7], Image data file applies lossless(File type code : 0) JPEG2000 [RD6].
5.2 Encryption
The encryption and decryption of GK2A UHRIT are based on a processing in accordance with the ECB
(Electronic Code Book) mode of DES (Data Encryption Standard) [RD 13]. Figure 5.2 shows the principle of
encryption and decryption.
The UHRIT File is encrypted using an encryption master key managed by NMSC. The inverse process,
decryption is also processed at LDUS at S/W level.
Figure 5.2 Principle of Encryption and Decryption for UHRIT
Compression Encryption UHRIT File S_PDU
- Applicable to image data - Lossless JPEG to UHRIT - Per observation mode - Optional
- DES - Per observation mode - optional
Encryption Key
Clear Data Encrypted
Data
Encryption
Decryption
Decryption Key
NMSC
GK2A UHRIT Mission Specification Document Issue 1.0 MAY 31, 2019
26
6 TRANSPORT LAYER
The Transport Layer generates TP_File with S_PDUs from session layer as byte unit and splits it into one or
more CP_PDU. The CP_PDU is the CCSDS Path Protocol Data Unit [RD3].
6.1 Transport File(TP_File)
In the Transport Layer, 10 byte TP_header is attached to the beginning of S_PDU and several bits (0~7) are
filled at the end of S_PDU to make it in byte units. The structure of TP_File is shown in Table 6.1 and
TP_Header is described as bellows.
Table 6.1 Transport File Structure
TP_Header S_PDU
Filler File Counter File Length
16 bits 64 bits 1 ~ (264
– 1) bits 0~7 bits
Table 6.2: UHRIT TP_Header
Field Bits Description
File Counter 16
UHRIT FD File Number:
VI004: 0~22
VI005: 23~45
VI006: 46~68
VI008: 69~91
NR013: 92~ 114
NR016: 115~137
SW038: 138~160
WV063: 161~183
WV069: 184~206
WV073: 207~229
IR087: 230~252
IR096: 253~275
IR105: 276~298
IR112: 299~321
IR123: 322~344
IR:133: 345~367
File Length 64 File Length(bits)
NMSC
GK2A UHRIT Mission Specification Document Issue 1.0 MAY 31, 2019
27
6.2 Space Packet (CP_PDU)
The CP_PDU are structur to Space Packet Hearder and Space Packet Data Field. The structure of Space Packet
is shown in Table 6.3 and Space Paket Header(Primary, Secondary) are described as bellows.
Table 6.3 Space Packet Structure
Packet Header User Data Field
Packet Primary
Header
Packet Secondary
Header 1 ~ 16,372 Bytes
CRC
6 Bytes 8 Bytes 4 Bytes
- Space Packet Checksum uses the CRC defined in ISO 13239 High-Level Data Link Control (HDLC).
- The CRC includes Primary, Secondary Header, and Payload data. We refer to CCSDS 133.0-B-1 [RD14].
Table 6.4 Space Packet Primary Header
Bits Field Description
3 Packet Version Number CCSDS protocol version
∙ 0 (fixed)
1 Packet Type Indicates whether this is a telecommand or telemetry packet
∙ 0 (fixed)
1 Secondary Header Flag Indicates whether this packet has a secondary header
∙ 1 (fixed)
11 Application Process
Identifier (APID) Identifies the specific data content of the packet
2 Sequence Flags
Flags for data segmentation
∙ 11: Single data
∙ 01: First segment
∙ 00: Contained segment
∙ 10: Last Segment
14 Packet Sequence Count Counter that ascends sequentially for packets with the same APID
16 Packet Data Length Packet size information (Bytes)
NMSC
GK2A UHRIT Mission Specification Document Issue 1.0 MAY 31, 2019
28
Table 6.5 Space Packet Secondary Header
Bits Field Description
16 Days Since the Epoch Number of days since the start of the standard J2000 epoch (January
1, 2000 12:00:00 UTC) for packet creation time
32 Milliseconds of the Day Milliseconds since start of day (12:00:00 UTC) for packet creation time
5 UHRIT Version UHRIT version number
∙ Current: 0
5 UHRIT Payload Variant Type of payload
∙ AMI: 0
2 Assembler Identifier
Ground system UHRIT assembly function hardware instance that
generated the packet
∙ PDS@NMSC: 0
∙ PDS@SOC: 1
4 System Environment
Ground system computing environment generating the packet
∙ Development: 0
∙ Integration and Test: 1
∙Operational: 2
NMSC
GK2A UHRIT Mission Specification Document Issue 1.0 MAY 31, 2019
29
7 NETWORK LAYER
The only function of Network Layer is to generate Virtual Channel ID (VCID) for each APID[RD7].
- Refer to Appendix B for APID and VCID
NMSC
GK2A UHRIT Mission Specification Document Issue 1.0 MAY 31, 2019
30
8 DATA LINK LAYER
Data Link Layer uses the “CCSDS, AOS Space Data Link Protocol, CCSDS 732.0-B-2”[RD9].
8.1 M_PDU
The Source Packet is entered into the M_PDU in units of 2,034 Bytes. In the M_PDU Packet Zone, no Space
Packet is input or multiple Space Packets can be input.
Table 8.1 M_PDU Structure
M_PDU Header M_PDU Packet Zone
RSVD Spare First Header
Pointer
End of Space Packet
(N) Space Packet (N+1)
Start of Space Packet
(N+2)
5 bits 11 bits 2,034 bytes
2,063 bytes
Table 8.2 M_PDU Header
Bits Field Description
5 Reserved Spare Reserved
∙ 0 (fixed)
11 First Header Pointer Offset to the location of the first Space Packet that starts in the
M_PDU Packet Zone (Byte)
NMSC
GK2A UHRIT Mission Specification Document Issue 1.0 MAY 31, 2019
31
8.2 AOS Transfer Frame
The M_PDU data is input to the AOS Transfer Frame.
Table 8.3 AOS Transfer Frame Structure
Transfer Frame Primary Header
Transfer
Frame
Data
Field
Frame
Error
Control
Field
Master Channel ID Signaling Field
Transfer
Frame
Version
Number
Spacecraft
ID
Virtual
Channel
ID
Virtual
Channel
Frame
Count
Replay
Flag
Virtual
Channel
Frame
Count
Usage
Flag
RSVD
Spare
Virtual
Channel
Count
Cycle
2 bits 8 bits 6 bits 24 bits 1 bits 1 bits 2 bits 4 bits
2 Bytes 3
Bytes 1 Bytes
6 Bytes 2,036
Bytes
2
Bytes
2,044 Bytes
- Transfor Frame Primary Header
Table 8.4 Transfer Frame Primary Header
Bits Field Description
2 Transfer Frame Version Number 0 (fixed)
8 Spacecraft ID Spacecraft ID (XXh)
6 Virtual Channel ID Virtual Channel ID (Table 6.4)
24 Virtual Channel Frame Count Virtual Channel Frame Count
1 Replay Flag Replay Flag
1 Virtual Channel Frame Count
Usage Flag Virtual Channel Frame Count Usage Flag
2 Reserved Spare Reserved Spare
4 Virtual Channel Count Cycle Virtual Channel Count Cycle
- Transfer Frame Error Control Field
Refer to Section 4.4.6 of the “CCSDS 732.0-B-2, AOS Space Data Link Protocol Blue Book” [RD9].
NMSC
GK2A UHRIT Mission Specification Document Issue 1.0 MAY 31, 2019
32
8.3 CADU
CADU is the addition of Sync Marker 0x1ACFFC1D (4 Bytes) to the beginning of the AOS Transfer Frame.
The following shows the CADU structure.
Table 8.5 CADU Structure
Sync (0x1ACFFC1D) AOS Transfer Frame
4 Bytes 2,044 Bytes
2,048 Bytes
NMSC
GK2A UHRIT Mission Specification Document Issue 1.0 MAY 31, 2019
33
9 PHYSICAL LAYER
The physical layer is a process performed in the CDAS, and performs BCH, LDPC FEC, and DVBS2 physical
layer frame modulation on the CADU stream transmitted by the PDS.
9.1 Baseband Layer Frame (BBFRAME)
The following table shows the BBFRAME structure of 8PSK 2/3.
Table 9.1 BBFRAME
BBFRAME(43040 bits)
BBHEADER DFL PADDING(if necessary)
80 bits Up to 42960 bits 43040 bits – BBHEADER-DFL
BBHEADER is defined as follows.
- MMATYPE definition: 0x7100
MATYPE-1: 0x71
MATTYPE-2: 0x00
- UPL: 0x0
- SYNC: 0xFF
Table 9.2 MATYPE-1 Field Mapping
TS/GS SIS/MIS CCM/ACM ISSYI NPD RO
11 = Transport 1 = single 1 = CCM 1 = active 1 = active 00 = 0.35
00 = Generic Packetized 0 = multiple 0 = ACM 0 = not-active 0 = not-active 01 = 0.25
01 = Generic continuous 10 = 0.20
10 = reserved 11 = reserved
NMSC
GK2A UHRIT Mission Specification Document Issue 1.0 MAY 31, 2019
34
9.2 XFEC Frame (XFECFRAME)
The following figure shows the XFECFRAME structure of 8PSK 2/3.
Table 9.3 DVB-S2 FECFRAME for 8PSK 2/3
BBFRAME BCHFEC LDPCFEC
43040 bits 160 bits 21600 bits
9.3 Physical Layer Frame (PLFRAME)
XFECFRAME is input as PLFRAME, and its structure is shown in the following table.
Table 9.4 DVB-S2 Physical Layer Framing
PLHEADER XFECFRAME
SOF PLSCODE SLOT 1 SLOT 1 SLOT 1 …
SLOT S-1 SLOT S
26 Symbols 64 Symbols 90 Symbols 90 Symbols 90 Symbols 90 Symbols 90 Symbols
90 Symbols S X 90 Symbols
(S + 1) X 90 Symbols
The following table shows the header structure of the PLFRAME.
Table 9.5 DVB-S2 PLHEADER
Symbols Field Description
26 Start of Frame(SOF) 0x18D2E82
16 Physical Layering Signal Code(PLSCODE) Refer to Section 4.4.6 of the DVB-S2 Standard
[RD10]
NMSC
GK2A UHRIT Mission Specification Document Issue 1.0 MAY 31, 2019
35
The parameter sets of the physical layer are specified in the Table 9.6.
Table 9.6 Parameters of UHRIT Communication Link
Parameters Values
Downloading frequency 8070 MHz
Bandwidth 20 MHz
Information data rate* 31 Mbps
Satellite EIRP 31.4 dBW
Minimum G/T of ground antenna (MDUS) 11.1 dB/K
Maximum BER 10-8
Coding BCH+LDPC 2/3 of DVB-S2 Standard
Pulse shaping Root-Raised Cosine with 0.25 of roll-off factor
Polarization LHCP
Modulation NRZ-L/8PSK
Length of one CADU 2048 bytes
NMSC
GK2A UHRIT Mission Specification Document Issue 1.0 MAY 31, 2019
36
APPENDIX
Appendix A: GK2A UHRIT Data Format and Procedures
Appendix B: GK2A LRIT/HRIT/UHRIT APID and VCID
In the future, the actual APIDs and VCIDs will be determined by NMSC’s broadcasting policy. Next table shows
current values of them. The APIDs and VCIDs will be deteremined w.r.t broadcasting data categories, not w.r.t
broadcasting channels(LRIT/HRIT/UHRIT).
Category 1 Category 2 Category 3 APID VCID
Image Data FD
VI004 0
0
VI005 1
… …
IR113 14
IR133 15
Reserved - 32 ~ 127 1 ~ 3
Additional Data
Alpha-numeric
Text - 128 4
Additional Data - 160 5